1. Field of the Invention
This relates to arrangements including adhesives for building pallet-loads of containers of the type made from wax-impregnated or treated paper or paperboard in order to reduce or eliminate the need for external restraints, such as straps, etc.
2. Description of the Prior Art
It is commonplace to ship fresh meats, vegetables, and fruits in paperboard containers packed in ice, the containers being made of a wax-impregnated material to impart strength in the presence of the moisture. The packing of these items sometimes takes place at temporary locations, often near the growing fields. Consequently, it is inconvenient to have automatic banding and strapping equipment on hand all the time. In addition this adds cost to the processor in terms of labor, equipment, and banding material.
It has been commonly known that palletized loads of boxes could be made unitary, or self-restraining, by applying to selected areas of containers an adhesive having greater bonding strength in shear than in tension, so the containers would resist normal slippage but be removable by pulling away from adjacent containers. Food Industries, July 1945, page 84. See also U.S. Pat. No. 3,322,323 to Greene et al, issued May 30, 1967; U.S. Pat. No. 2,578,583 to O'Brien, issued Dec. 11, 1951; and General Information Series 502 and 506 on Glued Loads issued by Freight Loss and Damage Prevention Bureau of the Association of American Railroads, 1946, reprinted 1966. (Copies are included for Examiner's convenience as they are now out of print.).
In spite of this previous work there is a need for a system which will function where wax-treated containers are used and are to be filled with or packed in ice or water.